Power utilities generate electrical power at remote plants and deliver electricity to residential, business or industrial customers via transmission networks and distribution grids. The power utilities may transmit large quantities of electric power over long distance transmission networks from power generating plants to regional substations, which then supply the power to local customers using the distribution grids.
The transmission networks and/or distribution grids may include overhead power transmission lines suspended by towers or poles. The transmission lines may, for example, be bare wire conductors made of aluminum. Instead of aluminum, copper wires may be used in medium-voltage distribution and low-voltage connections to customer premises.
Power is typically first transmitted as high voltage transmissions from the remote power plants to geographically diverse substations. The most common transmission voltages in use are 765, 500, 400, 220 kV, etc. Transmission voltages higher than 800 kV are also in use. From the substations, the received power is sent using cables or “feeders” to local transformers that further reduce the voltage. Voltages below 69 kV are termed sub transmission or distribution voltages. The outputs of the transformers are connected to a local low voltage power distribution grid that can be tapped directly by the customers.
Power failures at substations, local transformers or at customer sites often occur due to imbalanced loading or demand at the point of use. For example, residential circuit breakers often trip when appliances (e.g., dryers, ovens, etc.) overload the residential supply circuit. Similarly in a factory simultaneous operation of several industrial machines may overload and exceed the power supply to the factory.
Consideration is now being given to improving management of power supply and use at the customer level downstream of substations in a distribution grid. In particular, consideration is now being given to solutions to prevent overloading and prevent damage to supply lines and/or electrical loads.